Fig. 2: The role of traits in biogeographic dispersal.

a, Distributions of maximal differences of dispersal rates between most-dispersive and least-dispersive states per tetrapod class, in blue for body size–dispersal relationships, in yellow for life history–dispersal relationships. Centre line, median; box limits, first and third quartile; maximum extent of whiskers, box limits ±1.5 × interquartile range (that is, the distance between the first and third quartile). b, Proportions of different trait–dispersal relationships per tetrapod class, including only clades where maximal differences in dispersal rates between trait states were greater than 10%. ‘Extreme body size/life history’ refers to clades where a U-shaped relationship was inferred between traits and dispersal rates, that is, where species with extremely small or large body sizes, or fast or slow life histories had a dispersal advantage. c, Relative AICc weight of trait-dependent models compared with the entire set of candidate models, and across the entire range of binary trait thresholds (that is, the sum of AICc weights of trait-dependent models (+m2 and +m2x versions, Methods) compared with trait-independent models (base model and +x version), averaged across four binary thresholds). Centre line, median; box limits, minimum and maximum; n = 4 binary thresholds. The identified biological characteristics of better disperser lineages are indicated by symbols at the tip of the phylogeny, the size of which indicates the maximal difference in dispersal rates between trait states. Clades with life history trade-offs consistent with a fast–slow life history continuum are indicated by * at the end of the life history bars. d, Relationship between disperser characteristics in body size and life history analyses. The colours indicate the number of clades in which a given combination of body size–dispersal and life history–dispersal relationships were found. The symbols are the same as in c, indicating the shape of the relationships between traits (body size and life history) and dispersal rates.